Brig. Gen. Jeffrey Sinclair could face life in prison if convicted of all charges. / James Robinson, AP

by Michael Winter and John Bacon, USA TODAY

by Michael Winter and John Bacon, USA TODAY

Army Brig. Gen. Jeffrey Sinclair pleaded guilty Thursday to having improper relationships with three women but continued to challenge more serious charges.

Sinclair, 51, also pleaded guilty at Fort Bragg, N.C., to having pornography in Afghanistan and to conduct unbecoming of an officer and a gentleman, The Fayetteville Observer and other media outlets reported.

The former deputy commander of the 82nd Airborne admitted to committing adultery with his mistress, an Army captain. But he is fighting five charges, including sexual assault, resulting from allegations he forced her to perform oral sex, sodomized and groped her, had sex in public and threatened to kill her and her family if she revealed their affair.

Sinclair told the judge, Col. James L. Pohl, that his behavior was unbecoming an officer and had brought dishonor to the Army.

After acknowledging an encounter with one subordinate, Sinclair said, "Senior officers should not do that," the Los Angeles Times noted.

After Pohl accepted the guilty pleas, prosecutors dropped two lesser counts accusing him of pressuring a female major to send him nude photos, and of engaging in an improper relationship with a civilian woman who was a longtime friend.

Opening statements in Sinclair's court martial were tentatively schedule for Friday. The jury will be comprised of five generals.

Sinclair, a one-star general who remains on active duty at Fort Bragg, could face life in prison if convicted of the most serious charges. His accuser, the mistress who was 29 when the three-year relationship began, is posted in Arizona.

Sinclair, who is married with two sons, has said the affair was consensual. His lawyers have painted the woman as a scorned lover who only reported the sexual assault allegations after the general refused to leave his wife.

Sinclair told the judge the affair began after she asked him in March 2009 to watch a movie, which he said contained some nudity, in his trailer in southern Afghanistan.

"She wanted intercourse that night," he told Pohl, who asked how their sexual relation had begun. Sinclair said he decided immediately that "I wouldn't go there."

How did he know the captain wanted to have sex? Pohl asked.

"Probably when she took her top off, sir," Sinclair replied.

During a pretrial hearing, a top Pentagon lawyer testified that the lead prosecutor assigned to the case for nearly two years, Lt. Col. William Helixon, had urged that the most serious charges against Sinclair be dropped after he became convinced the evidence was too weak. Helixon was overruled by his superiors and then removed from the case last month, after suffering what was described as a profound moral crisis that led to his being taken to a military hospital for a mental health evaluation.

The case now heads to trial with a new lead prosecutor, Lt. Col. Robert Stelle, who said in court this week he has no interest in what his predecessor thought about the weakness of the evidence.

The case against Sinclair comes as the Pentagon grapples with a troubling string of revelations involving rape and sexual misconduct within the ranks. Thursday, the Senate defeated a bill to transfer control of sexual assault cases from military commanders to career prosecutors.

At the same time, Stars and Stripes reported that the Army's top prosecutor for sexual assault cases has been suspended for allegedly groping and trying to kiss a lawyer at a sexual-assault legal conference in 2011.

Lt. Col. Joseph Morse, who supervises 23 special prosecutors, is under criminal investigation but has not been charged.